Firmware is the computer code or software that is stored in an electronic device to control the operation of that device. Many electronic devices operate using a piece of firmware, e.g., wireless phones, set-top boxes, digital music players, etc. The device on which the firmware is stored and executed is frequently referred to as the host or the host device.
The firmware is typically stored in a non-volatile memory unit of the host device, for example, a flash memory unit. A non-volatile memory unit retains data even when power to the memory unit is discontinued. Consequently, the firmware is available when the host is activated.
When the device is started, the firmware is typically loaded into volatile memory, e.g., Random Access Memory (RAM), and executed by the processor of the host device. The processor's execution of the firmware causes the device to operate and provide the function or functions for which the host device was intended. In addition to providing the device's functionality, the firmware may also include a user interface allowing the user to control the functioning of the host device.
Frequently, it becomes necessary or desirable to change or upgrade the firmware in a host device. For example, a new firmware version may operate more robustly than an earlier version. A new firmware version may also provide additional features or extend the functionality of the host device.
Unfortunately, as with all software development, introducing a new version of firmware may cause unanticipated problems in the host device. Moreover, any particular host device may have a particular configuration of peripherals and additional applications or software that run on that host. Thus, the operating conditions on each host may be slightly different even if the host devices are identical. Consequently, a new firmware version may encounter problems on one host device that are not encountered on another host device.
When firmware is upgraded the typical upgrade procedure is as follows. The new firmware image is downloaded to the host device. The previous firmware image is deleted prior to downloading the new version or is overwritten by the new firmware image being downloaded.
The device is then restarted with the new firmware image being automatically loaded and executed as a consequence of the device being restarted. Hopefully, the host device will function as expected, perhaps with additional or enhanced functionality, while running the new firmware image.
If any problems are encountered, it will be necessary to determine if the difficultly has been caused by the new firmware or has some other cause. In order to diagnose this, or simply to return the device to operation, it may be necessary to reinstall the previous firmware version. This typically entails downloading the old firmware image to the host device. As before, the new firmware image is deleted prior to downloading the old version or is overwritten by the old firmware image being downloaded. The device is then restarted using the old firmware to see what impact this may have on the problems encountered with the new firmware version.
As can be appreciated by those skilled in this art, in order to troubleshoot and correct the problems with the new firmware, it may be necessary to switch between the old and new firmware versions several times and observe the resulting effect on the host device. This process is made extremely tedious by the need to download and install the desired firmware version each time a switch between versions is needed.